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Researchers measure coconut crabs’ remarkable squeezing force

A coconut crab can easily crack open hard-shelled coconut, thanks to the remarkable pinching or crushing power of the creature's scary claws. Known to biologists as Birgus latro, coconut crabs eat whatever they can get their strong claws on.

To measure coconut crabs' pinching power, Shin-ichiro Oka and colleagues from the Okinawa Churashima Foundation in Japan measured the crushing power of 29 crabs on the Okinawa Island with the help of a sensor.

To the surprise of the researchers, coconut crabs were found exerting a crushing power of 3,300 newtons, 4.5 times stronger than the grip strength of a typical man.

Sharing their findings, Oka said, "We expected the force would be very strong. But the actual powers exceeded our expectation. And we were also surprised that their pinching force was approximately 90 times of their body weight."

Among the top land-dwelling predators, crocodiles have the greatest squeezing forces of around 16,460 newtons. The coconut crabs come closer to predators like lions, tigers and hyenas, which have a squeezing force of around 4,450 newtons.

The researchers reported their findings about the 9-pound coconut crabs in a recent edition of the journal PLOS ONE.